No abstract

Čoh, M, Vodičar, J, Žvan, M, Šimenko, J, Stodolka, J, Rauter, S, and Maćkala, K. Are change-of-direction speed and reactive agility independent skills even when using the same movement pattern? J Strength Cond Res 32(7): 1929-1936, 2018-The purpose of this investigation was to determine whether there are differences between the 2 approaches to quantifying agility (preplanned vs. unplanned response) when reacting to a stimulus in an identical spatial scenarios. The study involved 45 male and 31 female trained athletes (age 21.2 ± 1.78 and 20.6 ± 1.27 years, body height 181.6 ± 8.31 and 167.7 ± 5.03 cm, and body mass 78.9 ± 11.33 and 63.3 ± 8.65 kg, respectively). A light-based reactive training system was used to measure the time to completion in a task that assessed agility by change-of-direction speed (CODS) in a preplanned condition and reactive agility (RA) in an unplanned condition across 4 spatial configurations. Sprint performance in a 30-m sprint and lower limb reactive power in a 10-m single leg jump test was also measured. Significant differences (p ≤ 0.05) were found between men and women in all tests and between performance in the CODS and RA condition for each spatial configuration. Significant correlations were observed between 30-m starting sprint speed and CODS and RA performance measured in a semicircle (r = 0.62, r = 0.60) and lateral (r = 0.54, r = 0.58) configuration in male athletes. The present findings suggest that CODS and RA are 2 different and independent skill domains that define agility. These qualities should be diagnosed by discrete assessments and enhanced by different training methodologies.

To the best of our knowledge, this is the first comprehensive analysis of MSI among SAF members showing that the currently used injury surveillance system in SAF, that reports only the prevalence of time-loss injuries (4.9%), is probably underestimating the true and overall MSI prevalence (48.8%) in SAF members, suggesting a need for a better injury registration process. Based on the most frequent injury locations, preventive measures in SAF should focus on knee and ankle injuries in males with previous lower limb injuries. A best preventive approach would probably be to train smarter and harder to develop the physical capability to better protect against those injuries.

The aim of this study was to determine how elite volleyball players employed the arm swing (AS) to enhance their jump performance. The study assessed how the AS influenced the duration and magnitude of the vertical ground reaction force (VGRF) during the main phases (preparatory, braking and accelerating) of the countermovement vertical jump (CMVJ), the starting position of the body at the beginning of the accelerating phase and the moment when the AS began contributing to increasing the jump height. Eighteen elite volleyball players performed three CMVJs with and without an AS. Kinetics and kinematics data were collected using two Kistler force plates and the C-motion system. The time and force variables were evaluated based on the VGRF, and the position of the body and the trajectory of the arm movement were determined using kinematic analysis. The AS improved the CMVJ by increasing the jump height by 38% relative to jumping without an AS. The AS significantly shortened the braking phase and prolonged the accelerating phase, however, it did not influence the preparatory phase or the overall jump duration. The AS also significantly increased the average force during the accelerating phase as well as the accelerating impulse. The AS upward began at 76% into the overall jump duration. The AS did not influence the body position at the beginning of the accelerating phase. These findings can be used to improve performance of the CMVJ with the AS and in teaching beginning volleyball players proper jumping technique.

This study assessed differences in agility performance between athletes of team and individual sports by assessing change-of-direction speed (CODS) as pre-planned agility and reactive agility (RA) as non-planed in different spatial configurations. The study involved 36 individual (sprint, hurdles, jumping, tennis, and judo) and 34 team (soccer, basketball, and handball) athletes. CODS and RA were measured with a light-based reactive training system in a frontal (FR), universal (UN), semicircular (SC), and lateral (LA) design. Lower limb power and sprint performance were also measured in a 10 m single leg jump test and 15 m sprint. Individual athletes showed significantly better performance in three of the eight agility tests: LA-RA, UN-RA, and SC-CODS (p < 0.008, p < 0.036, and p < 0.027, respectively) and were found to present stronger correlations (p < 0.01) between jump test performance and the CODS condition. Team athletes showed stronger associations between sprint performance and the CODS condition. In the RA condition both jump and sprint performance showed stronger correlations in the group of individual athletes. Agility performance as measured by CODS and RA should improve with enhanced of motor proficiency. Finally, the tests applied in this experiment seem to be multidimensional, but require spatio-temporal adjustment for their implementation, so that they meet the requirements of the particular sport.